TOIM3232

Vishay Telefunken

Not for new designs

Rev. A1.1, 02-Apr-01

4 (9)

www.vishay.com

Document Number 82521

Software for the TOIM3232

The control word is composed of two characters, written in hexadecimal, in format: YZ.

UART Programming

For proper operation, the RS232 must be programmed

to send a START bit plus an 8 bit data word, YZ and

no STOP bit for every word sent. The transfer rate for

programming must be identical with the formerly

programmed

data

rate,

or

after

resetting

the

TOIM3232, the default rate of 9600 bit/s is used.

Software algorithm

Step

RESET

BR/D

RD_UART TD_UART

RD_IR

TD_IR

Comments

1

HIGH

X

X

X

X

X

Resets all internal registers. Resets

IrDA default data rate of 9600 bit/s.

2

LOW

X

X

X

X

X

Wait at least 7

ms.

3

LOW

HIGH

X

X

X

X

Wait at least 7

ms.

The TOIM3232 now enters the

Control Word (programming) mode.

4

LOW

HIGH

YZ

with Y = 1

for

1.627

ms

Y = 0

for 3/16 bit

length

X

X

X

Sending the Control Word YZ.

Send ‘1Z’ if 1.627

ms pulses are

used. Otherwise send ‘0Z’ if 3/16 bit

pulses are used. ‘Y6’ keeps the 9.6

kbit/s data rate, whereas the ’0Z’

selects the 3/16 bit length pulses.

Z = 0 sets to 115.2 kbit/s. Wait at

least 1

ms for hold-time.

5

LOW

LOW

DATA

DATA

DATA

DATA

Data communication between the

TOIM3232 and the RS232 port has

been established by BR/D LOW.

The TOIM3232 now enters the data

transmission mode. Both RESET

and BR/D must be kept LOW (‘0’)

during data mode. Software can

reprogram a new data rate by

restarting from step 3.

The UART also must be set to the

correct data rate *).

*)

For programming the UART, refer to e.g., National Semiconductor’s data sheet of PC 16550 UART.